Aortic aneurysms and the degeneration of the vasculature in general represent a significant medical problem for the general population. Aneurysms within the aorta presently affect between two and seven percent of the general population and the rate of incidence appears to be increasing. This form of vascular disease is characterized by degeneration in the arterial wall in which the wall weakens and balloons outward. Until the affected artery is grafted through open repair or treated with a stent graft endovascularly, a patient with an aortic aneurysm must live with the threat of aortic aneurysm rupture and death.
One known clinical approach for patients with an aortic aneurysm is a surgical repair procedure. This is an extensive operation involving dissection of the aorta and reinforcement of the aneurysm wall with a prosthetic graft.
Alternatively, there is a significantly less invasive clinical approach to aneurysm repair known as endovascular grafting. Endovascular grafting involves the placement of a prosthetic arterial stent graft within the lumen of the artery. To prevent rupture of the aneurysm, a stent graft of tubular construction is introduced into the blood vessel, and is secured in a location such that the stent graft spans the length of the aneurysmal sac. The outer surface of the stent graft at its ends is sealed to the interior wall of the blood vessel at a location where the blood vessel wall has not suffered a loss of strength or resiliency, such that blood flowing through the vessel is diverted through the hollow interior of the stent graft away from the blood vessel wall at the aneurysmal sac location. In this way, the risk of rupture of the blood vessel wall at the aneurysmal location is significantly reduced and blood can continue to flow through to the downstream blood vessels without interruption. However, despite the advantages of endovascular grafting over other surgical procedures, there is, nonetheless, continued progression of the aneurysm disease.
A salient feature of aneurysm formation is the gradual degradation of extracellular components, such as collagen and elastin, as well as the loss of resident cells, namely smooth muscle cells and fibroblasts. The cells in a healthy vessel perform many and varied functions, including providing reinforcement to the vessel wall and, importantly, replenishing the extracellular components. The diminished cellular presence observed in diseased arteries directly and adversely impacts the vessel wall ultrastructure.
The field of cell replacement research and tissue engineering currently is one of the major focuses of medical technology. An exciting area of tissue engineering is the emerging technology of “self-cell” therapy, where cells of a given tissue type are removed from a patient, isolated, perhaps mitotically expanded and/or genetically engineered, and ultimately reintroduced into the donor/patient with or without synthetic materials or other carrier matrices. One goal of self-cell therapy is to help guide and direct the rapid and specific repair or regeneration of tissues. Such self-cell therapy is already a part of clinical practice; for example, using autologous bone marrow transplants for various hematologic conditions. The rapid advancement of this technology is reflected in recent publications that disclose progress toward bone and cartilage self-cell therapy. Moreover, similar advances are being made with other tissues such as cardiac muscle, liver, pancreas, tendon and ligament. One of the greatest advantages of self-cell therapy over current technologies is that the autologous nature of the tissue/cells greatly reduces, if not eliminates, immunological rejection and the costs associated therewith.
Thus there is a desire in the art to slow, reverse, or potentially cure the aneurysm disease state by using minimally invasive procedures while reducing or eliminating immunological rejection. The present invention satisfies this need in the art.